[3] Since these lines were written Doctor Boris Sidis, in his “Psychology of Laughter,” has criticised the Bergson theory in more detail but on somewhat different grounds. Doctor Sidis’s own theory, briefly, is that the laughable is not the “mechanical” but the “stupid.” Or, as he himself expresses it, “Allusion to human stupidity is at the root of all comic.” [4] The psychology of dreams and their practical significance will be dealt with in some detail in my forthcoming book on “Sleep and Sleeplessness.” INDEX Adenoids, and delinquency, 27; and laziness, 173-174. Ampère, A., 84. Baby talk, dangers of, 49-51, 136. Bain, A., 199. Balzac, H. de, 99, 166-167. Berle, A. A., 49-50, 136. Bidder, G., 84. Binet, A., 62. Boccacio, 99. Brady, J. G., 16-18. Bruns, Doctor, 241-242. Burke, A. H., 15-16. Buxton, J., 84, 85. Chabaneix, P., 89. Childhood, impressionability of, 30-35, 41-45, 60-63; mental activity in, 163-164; hysteria in, 221-245; results of fear in, 258-274. Children’s Aid Society, 13-18. Cicero, 106. Colburn, Z., 82-84. Coleridge, S. T., 78. Colours, psychology of, 57-59. Condillac, 79. Coriat, I. H., 255-256, 266-268. Coulter, E. K., 11. Dante, 88, 99. Darwin, C., 91, 165, 168, 180-183, 186, 201, 203, 250. Dase, Z., 84. Davy, H., 166. Delinquency, chief factors in, 5-19; physical defects and, 19-27, 162. Dental defects, and delinquency, 22-27; and laziness, 174-176. Diderot, D., 89. Dreams, and genius, 75-81; and disease, 260, 265, 267-268, 270-272. Dubois, P., 28, 285. Dugdale, R. L., 7, 10. Education, suggestion in, 39-68; importance of early, 67-68, 114-117; instances of early, 119-157; helps in early, 286-289. Eliot, C. W., 64-65. Ellis, H., 57, 106. Environment, and crime, 5-19; and ill-health, 52-55; and mental development, 60, 109, 136-137; and hysteria, 232-234; and general welfare, 283-284. Eugenics, 5-6. Eye trouble, and delinquency, 21-23; and laziness, 177-178. Fear, function of, 250; abnormal, 251-256; as cause of nervous diseases, 257-274. Fénelon, 106. Fleury., M. de, 179, 183-185. Franklin, B., 79. Galileo, 91, 106. Gauss, K., 84. Genius, contrasting theories of, 71-75; and dreams, 75-81; the subconscious in, 86-94; and hard work, 95-101; interest and, 102; precocity of, 105-107; longevity of, 107-108. Goethe, 87-88. Gourmont, R. de, 89. Habits, formation of, 42-43. Hall, G. S., 196, 213. Hallam, H., 106. Hecht, D’O., 227-229. Heine, H., 165. Henry, P., 166. Heredity, and delinquency, 5-19; and genius, 71; and hysteria, 264. Heyne, C. G., 142. Hobbes, T., 105-106, 198-199. Holmes, A., 24.